EXFO FTB-4 Replacement Battery NF2047HD 7.2V 6600mAh

EXFO FTB-4 — 7.2V Li-ion Replacement Battery (NF2047HD)

This is a 7.2V 6600mAh Li-ion battery for the EXFO FTB-4 modular optical test platform. It fits the FTB-4 chassis used for fiber optic network diagnostics, installation verification, and field survey work. OEM part numbers covered: NF2047HD, NF2047HD29, NF2047HD34, and NF2047QE34.

• FTB-4 platform compatibility: The FTB-4 accepts interchangeable test modules — OTDR, optical power meter, and inspection probes. Each module draws differently from the same battery bus. This pack matches the voltage rail and connector pinout the FTB-4 BMS expects, so module switching does not trigger a protection event.
• Bench tested on actual hardware: We ran the pack through FTB-4 module initialisation sequences, including OTDR laser warm-up and probe power-on cycles. The BMS held steady through each current spike at module activation and did not trip into protection mode during sustained logging.
• Pre-deployment calibration cycle: After fitting this battery, run a full calibration cycle through the FTB-4 instrument menu before heading to site. The platform maps battery state during calibration — skipping this step causes premature low-battery warnings during your first measurement session, even with a full charge.

BMS cutoff during OTDR or probe module power-up on the FTB-4

When the FTB-4 initialises a test module, the inrush current at power-up can briefly exceed what an aged or depleted cell can supply without a voltage sag. If the pack voltage dips below the BMS protection threshold during that spike, the battery cuts out entirely. This is more common with OTDR modules, which pull a sharp current burst during laser warm-up. A fresh pack at full charge handles this spike without the sag — if the unit cuts out on module load, charge the battery to full before re-seating it.

FTB-4 showing erratic battery percentage at reboot after pack swap

After fitting a new pack, the FTB-4 may display an inconsistent charge percentage — jumping between values or reading lower than expected across the first few power cycles. The instrument's voltage-threshold indicator is recalibrating to the new cell's discharge curve and has not yet built a complete state-of-charge map. Run the battery through one full charge-to-discharge cycle in the field, then recharge fully. By the second full cycle, the percentage display stabilises and tracks accurately to actual cell voltage.